DOHA - The head of the Qatar Investment Authority said Wednesday that the lingering Gulf political crisis was having little impact on the $300 billion sovereign wealth fund of the gas-rich nation.

In a rare public appearance, Sheikh Abdullah bin Mohamed bin Saud Al-Thani, chief executive at the QIA, said there was "no problem" for the fund despite the crisis passing the 100-day mark.

"We are still open for business and business as usual," Sheikh Abdullah said in an address at the Carnegie Mellon University in Qatar.

"We are fine," he added.

Qatar has found itself regionally isolated since June 5 after Saudi Arabia, the United Arab Emirates, Bahrain and Egypt cut all ties, accusing Doha of bankrolling Islamist extremists and being too close to Iran.

The emirate denies the charges and has moved to realign itself politically and economically.

Pressed on the impact of the crisis several times, Sheikh Abdullah said the QIA's exposure to those countries leading the boycott was "very, very small" and added that the fund would continue its recent policy of targeting hi-tech and infrastructure companies in the United States.

"The future is technology," he said.

Moody's Investor Service said on Wednesday the regional dispute was hurting the economies of all countries involved, with Qatar being impacted the most.

It estimated that around $30 billion flowed out of Qatar's banking system in June and July and that Doha used $38.5 billion in the two months to support the economy.

Among the companies in which the QIA was investing were those in the health sector using hi-tech solutions for cancer treatment, said Sheikh Abdullah.

In 2015 he announced that the QIA would invest up to $35 billion in the United States over the following five years, after targeting high-profile acquisitions in Europe.

Last December it was also announced the fund would invest $10 billion in US infrastructure projects.

He said Wednesday that around half of that $45 billion had been invested.

The QIA has opened an office in New York and will do so soon in the Silicon Valley, he added.

"If you want to invest in the States, you have to have boots on the ground," he said.

Earlier this week it was announced that the QIA and Swiss commodities trader Glencore had sold a major part of a stake they had only recently acquired in Russian oil giant Rosneft to Chinese conglomerate CEFC.

The QIA is considered one of the world's biggest sovereign funds, swollen by Qatar's massive gas and oil revenues.